Class, group, subgroup

Classes represent separate sets of students who share the same curriculum and usually attend their courses together (same subjects, teachers and classrooms), with a single exception: division into groups, that is, custom subsets with a marginally adapted curriculum (subdivision by options, ability levels, gender, alphabetical order…). Two different classes never have students in common.

In Omniscol, you always start from the class, then, inside each one, you create groups whenever the whole class does not follow the same course. Subgroups refine this split when a group must itself be subdivided: a group attached to another group, in a parent-child relationship, becomes a subgroup.

Class divisions, alignments and groups of groups are not extra levels in the hierarchy. They are ways of organizing or linking groups depending on the use case.

Overview

Read it as follows:

• a class contains groups;
• a group can contain subgroups;
• a class division organizes groups of the same class that share out the students;
• an alignment links groups from different classes for a shared course;
• a group of groups builds an explicit, reusable grouping, especially when the grouping must evolve.

This diagram shows several classes, with several groups, some in a division, others aligned, sometimes both. The second foreign language is an exclusive option: a student attends either the German, the Spanish or the Italian course. That is why the different language options are declared as a division: they can be scheduled simultaneously (provided different teachers teach each of the languages). Few students take German in Grade 9 A and Grade 9 B: they are therefore brought together to follow the same courses — that is the purpose of the alignment; mirrored lessons are created in each class, so they are scheduled simultaneously. The same goes for the Latinists of Grade 9 B and Grade 9 C.

This diagram also illustrates a classic resource-saving pattern, "3 groups across 2 classes": classes Grade 9 B and Grade 9 C are each divided into Technology 1 (20 students) and Technology 2 (10 students). By aligning the two Technology 2 groups, the school merges the two small groups and runs only three technology courses instead of four — all of equivalent size (20 students), with one fewer teacher and one fewer room needed.

Class: the base level

A class is the default reference entity. Depending on the context, it can represent:

• a school class,
• a year group,
• a cohort,
• a session,
• a track.

When a course concerns the whole class, no extra group is needed: the course is simply attached to the class.

Group: a subdivision of a class

A group is always a subdivision of a single class. All its students remain students of the parent class.

Classic examples:

• Group A / Group B for an alphabetical split;
• Lab-A / Lab-B for lab-session half-groups;
• Spanish / German / Italian for exclusive second-language options;
• Advanced English / Intermediate English / Basic English if the school works with ability groups;
• Boys / Girls in the contexts where this split exists;
• Elective Marketing, Elective Finance, Elective Data in a higher-education elective set.

Strong recommendation: create one group per clear pedagogical use, even if the students are sometimes the same. For example, Latinists and Hellenists are better than reusing a generic Options group. Otherwise, timetable reading, diagnostics and cross-class groupings quickly become ambiguous.

Important consequences:

• subgroups stay within the scope of the class;
• they inherit their parent's logic;
• they are useful when you have several levels of subdivision;
• they only make sense if the structure stays readable.

Subgroups are very handy when they are also used with class divisions:

• groups A and B in a division;
• groups A1 and A2 in a division;
• groups B1, B2 and B3 in a division.

Automatically, A1 and B3 are in a division, just like A2 and B1, and so on. This relationship is deduced from the combined logic of divisions and parent-child links.

Subgroups are groups that were dragged and dropped onto a parent group. The page Group hierarchy goes further into advanced uses: inherited divisions, inherited constraints and time masks.

Class division: splitting one class into exclusive groups

A class division is used between groups of the same class when the students are spread across several mutually exclusive groups. Omniscol is constraint-based scheduling software, so by default groups are assumed to potentially share at least one student: declaring a division between groups lifts that constraint. Explicitly, groups of the same division are not in conflict.

The idea to remember:

• every student must belong to only one (or none) of the division's groups;
• these groups can then carry different courses in parallel;
• Omniscol knows this is not a student conflict.

Examples:

• Lab-A and Lab-B run two different lab sessions at the same time;
• Spanish, German and Italian share the same option time slot;
• Group A and Group B alternate simultaneous activities in two rooms;
• Advanced English, Intermediate English and Basic English follow three different courses in parallel.

Within a single class, the division is therefore the right tool when you want to say: "these groups share out the students, they can be placed in parallel".

Note: Omniscol has an optional mode of operation where students are directly assigned to classes and groups at the timetable level. In that case, divisions can be deduced automatically (no student overlap between groups = division).

Subgroups and class divisions

With subgroups, the division logic propagates along the hierarchy. If Lab-A and Lab-B are in a division, the subgroups of Lab-A and those of Lab-B inherit this separation between branches.

Example:

• Lab-A and Lab-B are in a division;
• Lab-A1 and Lab-A2 are subgroups of Lab-A.

Omniscol then knows that a course on Lab-A1 does not conflict with a course on Lab-B, without you having to redeclare every combination by hand.

However, if you want to subdivide Lab-A into several branches that also share out the students, you must explicitly define this subdivision in the hierarchy and, if needed, its own division.

Alignment: one course shared across several classes

An alignment is used when several groups from different classes actually follow the same course, in the same time slot, with the same teacher and in the same classroom.

Classic example: the Latinists of Grade 7 A, Grade 7 B and Grade 7 C share a single Latin course.

Alignment is very useful for cross-class options or electives, but it is more rigid than a simple group: everything that is aligned lives together.

Important condition: it must be the same subject across the classes involved.

In other words, if you want a shared course across several classes, those classes must actually share the subject used by that lesson.

Example:

• Marketing shared across several classes: yes;
• Marketing B3 in one class and Marketing M1 elective in another: no, not if they are two distinct subjects in the timetable structure.

In higher education, this often leads to avoiding subjects too specific to a single program when you know courses will be shared. It is better to plan a subject common to the classes that must share lessons.

Alignments are better suited to secondary schools: the point is to create mirrored lessons, and to declare the dynamic grouping logic. The drawback is having to respect this mirror: you must create as many lessons as there are groups in the alignment, with the right groups assigned in each class, and everything must be symmetrical: teacher(s), classroom, resources, etc. If a lesson carrying a group of an alignment is positioned, a mirrored lesson must exist in each class, with its corresponding aligned group.

The advantage is the ability to create complex courses with alignments. You can have a shared Latin course on week A, and a different, non-grouped course in each class.

If these constraints are not offset by the benefits, consider groups of groups instead.

Group of groups: an explicit, editable grouping

A group of groups gathers several groups into a named, editable and reusable grouping. The group of groups is then used like any other group.

It is particularly useful:

• in higher education and continuing education;
• when the composition of a grouping may change;
• when you want to keep a readable, traceable structure.

Example: a shared seminar brings together students from M1 Marketing, M1 Finance and Elective Data. The lessons are scheduled with the group of groups, then, later, a fourth group joins the arrangement: simply add it to the group of groups and every lesson is attached to it.

As with alignments, the shared lessons must rely on a common subject across the classes involved. The group of groups brings audiences together; it does not replace the consistency of the subject used for the course.

If you need to bring together whole classes, first create in each class a group representing that whole class, then use these groups in the alignment or the group of groups. Classes are never aligned directly without going through groups.

Assigning several groups directly to a lesson

It is possible to assign several groups directly to a lesson, without first creating a named group of groups.

This is useful:

• for a one-off need;
• to quickly test a grouping;
• for an exceptional lesson that does not justify a dedicated structure.

But it is not the best choice as a long-term model:

• it is less readable over time;
• it is less traceable than a named grouping;
• it becomes harder to understand the pedagogical intent if this pattern repeats often.

In practice:

• for lasting use, prefer an explicit group of groups;
• for a one-off need, directly assigning several groups is very handy.

However, avoid mixing, on the same lesson, a parent group and one of its subgroups: this is generally not a clean model of the audience involved.

Summary table